Inode Tutorial

Inodes are an integral part of UNIX-like operating systems, as the ones used in the hosting industry and the one we use for our Shared Hosting Servers. To understand why there are limits on the number of Inodes you have at your disposal, you must understand what an Inode represents.

When a file is written, the information contained in that file is stored in a data block. However, in order for the system to know when to read the file or when was the file last edited an Inode is created with the following metadata:

• Mode/permission
• Owner ID
• Group ID
• Size of file
• Number of hard links to the file
• Time last accessed
• Time last modified
• Time inode last modified

As you notice, the Inode does not contain information about the name or path of the file. This is stored in the directory itself as the directory is actually a table that contains the filenames in it as well as the inodes corresponding to them.

As the maximum number of inodes is set when the filesystem is created (configuring the shared server as part of the fleet for set datacenter location) and dedicated space is allocated for them you can run out of inodes before you run out of space for data which is why you have both Inode (File Usage) and Data (Disk Usage) in your cPanel which you can check on at all times. The number of Inodes available to you is in accordance with the other resources of your shared hosting plan.

In the following tutorials, we will also take a look at the process of checking your Inodes, using our dedicated Inode cPanel tool in order to keep your hosting account healthy, common Inode generators, how to maintain them and overall best practices regarding Inodes.